Wanted: 4346 Holley dated April or May of 69

[98form]

I have an L78 engine that is not a numbers matching, but is loosely date correct with an assembly date of 4/02. The assembly date of my car is 2nd week of June. How far was the lead time on these carburetors? From what I have read in the engine assembly order and car assembly process, the carburetor was not installed when the engine was assembled, but when the engine was installed in the car. Does that sound right to you guys?